Deadly Errors. Many lowrise building designs include parking areas or poorly reinforced retail space. This has proven to be a major collapse point during quakes. But most weaknesses can be addressed with remedial reinforcement of three types, shown on the following slides.
Column Spacing. In some cases, simply adding more structural columns increases seismic resistance. But building with slender first floor columns are not necessarily weak. If lateral forces are addressed with sheer walls, column sizes take on less importance.
Key Concern. Especially where the base of the building is completely open, bracing can take the place of shear walls. In an earthquake, lateral forces are typically the ones most likely to cause major collapse.
Space Saver. If loss of indoor space is a big concern, the ancient technique of applying external buttresses can accomplish the same strengthening as other techniques.. Source: Fema 454: Designing for Earthquakes